* Reset of all peripherals, Initializes the Flash interface and the Systick. Anyway, you are right, it misses to set the timer in slave mode reset mode (SMS b100) and to select the right trigger, so that the CCR1 register value is steady after the input signal trigger occurred. Feeding a 2KHz signal to TIM4 Ch2 pin (PB7), I don’t see my interrupt handler function getting triggered at all. Currently I’m trying to port over the PWMInput example from STM32CubeF4 to work with Mbed, but haven’t any luck. Uint16_t Channel4RisingTimeLast=0, Channel4RisingTimeNow, Channel4FallingTime I’m trying to measure a couple of low frequency signals (0-10000Hz) using input capture timers on F401RE. Uint16_t Channel3RisingTimeLast=0, Channel3RisingTimeNow, Channel3FallingTime Uint16_t Channel2RisingTimeLast=0, Channel2RisingTimeNow, Channel2FallingTime Uint16_t Channel1RisingTimeLast=0, Channel1RisingTimeNow, Channel1FallingTime Uint16_t Channel1Percent, Channel2Percent, Channel3Percent, Channel4Percent

Uint8_t Channel1Edge = 0, Channel2Edge = 0, Channel3Edge = 0, Channel4Edge = 0 Uint16_t Channel1Period, Channel2Period, Channel3Period, Channel4Period Uint16_t Channel1HighTime, Channel2HighTime, Channel3HighTime, Channel4HighTime The following are more important codes /* Private variables -*/ The following is my STM32CubeMx configurationĨ. There is a problem here, for example, when the rising edge time is in the previous cycle and the falling edge time is in the next cycle, then a timer period is added before the falling edge-rising edge. When a rising edge is captured, the polarity is set to the falling edge capture, and so on, so we can get the high time and cycle time pay attention to set Good sign Then I need to set the capture to the rising edge at the very beginning. The Timer of STM32, except TIM6 and TIM7, other timers have input. So whether it is set to capture on the rising edge or capture on the falling edge, you can only get the cycle time of the whole pulse if you want to get the high level as a percentage of the whole cycle? The input capture mode can be used to measure the pulse width or measurement frequency. If the set polarity edge is detected, the current count value will be saved and the interrupt will be triggered.įor example, if the timer is set to TIM2, the prescaler is 719, and the counting period is 0xFFFF, the TIM2 10us counts once, counts to 0xFFFF, and reloads to 0 now the set input capture polarity is captured by the rising edge, then when a channel is captured After a rising edge, the interrupt is triggered and the current count value exists in the CCR value of the corresponding channel Simple explanation: the timer is always counting. The captured data in the TIMx_CCRx register also clears CCxIF. Write CCxIF=0 to clear CCxIF, or read storage Is high, then the repeat capture flag CCxOF (TIMx_SR register) is set. If the capture event occurs, the CCxIF flag is already

When a capture event occurs, the corresponding CCxIF flag (TIMx_SR register) is set, if openĪn interrupt or DMA operation will generate an interrupt or DMA request. The application uses TIM2 and TIM3 (input capture of pilot commands from an RC receiver) and also TIM4 (PWM outputs to quadcopter motor controllers).In input capture mode, when the corresponding edge on the ICx signal is detected, the current value of the counter is latched into the capture/compare register. It makes use some lower level bit manipulation of TIM2-4 for interrupt based input capture of pulse inputs as well as hardware PWM control of outputs. This was originally developed around a slightly earlier version of Roger’s libmaple based STM32duino core ( ). I’m hoping to gain enough understanding of this core and STM32 timer control to port this flight controller application ( ). I’ll document my efforts here in this thread. I’m trying to put together a minimum Input Capture hardware timer example using Interrupts to measure an input pulse stream (single pulse stream for now, with 6 total inputs to eventually be captured for my intended application.

Stm32 hal input capture